It is generally known to use a cross-linked polyethylene pipe to lead hot and cold water. By using cross-linking in a polyethylene pipe, the pipe obtains a heat tolerance, especially in long lasting usage, and in usage under pressure.
It is also generally known that the weakness of a cross-linked polyethylene pipe is its penetration of oxygen that causes, especially in circulating water systems, the increase of the oxygen content and, as a result of that, the oxidization of the metal parts of the system.
Accordingly, there is a need for an improved method to produce plastic pipe in layers.